Can You Take Benadryl With Nyquil?


Our pharmacist has responded to a query about whether it is safe to take (diphenhydramine) Benadryl with Nyquil.


Generally, it is not advised to take (diphenhydramine) Benadryl with Nyquil at the same time, as they both contain sedating antihistamines

NyQuil contains doxylamine, a sedative antihistamine that is very similar to diphenhydramine, the key component of Benadryl. 

Both of these drugs belong to the same group of sedating first-generation antihistamines.

It is generally not advised to take two first-generation antihistamines together as this is known as ‘duplicate therapy’ and increases the risk of side effects. It would usually be better to just take one of the two antihistamines.

What Is Benadryl?

Benadryl is identified as a first-generation antihistamine with a generally observed effect of 4-6 hours when administered from 25 mg to 50 mg.

First-generation antihistamines are known to have sedative and CNS (central nervous system) depressant effects.

Many people cannot bear the sedative qualities of Benadryl (diphenhydramine) during the day, so they usually only take it at night to help with sleep problems.

What Is NyQuil?

Nyquil is a medication for cold and cough relief that includes the medication doxylamine, and acetaminophen for reducing fever and discomfort, as well as dextromethorphan for suppressing coughing.

Doxylamine belongs to the same medicine class as Benadryl (diphenhydramine), which are both first-generation antihistamines with sedative effects.

Interaction Explained

Both doxylamine and Benadryl (diphenhydramine) are in the same class of medication and act similarly in the body.

The histamine-1 receptor in the body is blocked by these drugs, meaning histamine cannot bind to it and thus the common symptoms such as a runny nose and watery eyes are prevented.

It is not recommended to take both drugs together since they act in the same manner. Combined use generally won’t provide any more benefit than taking either alone. 

Additionally, taking them together not only increases the risk of excessive sedation, but it greatly increases the risk of additional adverse effects such as:

  • Diarrhea
  • Breathing difficulties
  • Dry mouth 
  • Dry eyes 

High dosages of sedative antihistamines have been linked to feelings of excitement, restlessness, and agitation.

Is It Ever Okay To Use Them Together?

It could be beneficial to merge the two, thus signifying that it may be a wise decision.

Significant evidence suggests that Benadryl (diphenhydramine) may be beneficial in managing allergic reactions.

According to research that Benadryl (diphenhydramine) is effective in helping to reduce the itching and swelling associated with bee stings and poison ivy reactions.

If you have previously taken Nyquil and are experiencing an allergic reaction, a dose of Benadryl (diphenhydramine) could help without the risk of serious side effects.

How Long To Separate

Although it is not recommended to take both Benadryl and NyQuil on the same day, it can be done since both have a brief period of effectiveness.

Due to the fact that each dose of Benadryl and NyQuil lasts between four to six hours, as long as they are taken at intervals of at least this duration apart should not cause any interaction between the two.

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Possible Side Effects of Taking Both

When taking both Benadryl and Nyquil, it is important to be aware of the potential side effects that can occur. 

While this combination is often used to treat common cold symptoms, users must carefully consider the possible consequences before proceeding. 

For instance, some people may experience a heightened sense of drowsiness or dizziness due to the combined effect of these two medications. 

Additionally, patients may also experience an upset stomach or blurred vision if taken together in certain doses. 

It’s important for individuals considering taking both Benadryl and Nyquil to assess their overall health first before starting treatment. 

If you have pre-existing conditions such as asthma or diabetes, you should consult your doctor before taking any additional medications which could interfere with other prescriptions you may be on.

When Should You Seek Medical Attention?

It is important to know when to seek medical attention for common cold and flu symptoms. If you are considering taking Benadryl with Nyquil.

It is important to understand the potential risks associated with this combination of medications. 

While these over-the-counter medications are generally considered safe together, there are some scenarios in which medical attention can be beneficial or even necessary.

If you have been experiencing fever, difficulty breathing, chest pain, severe fatigue, or confusion lasting more than 24 hours while taking Benadryl with Nyquil, then it may be time to seek medical help. 

Other signs that warrant a trip to the doctor can include a persistent cough that produces yellow or green mucus as well as a sore throat that lasts longer than 5 days. 

FAQs For Taking Benadryl With Nyquil

Can You Take Benadryl With Nyquil?

Yes, Benadryl and Nyquil can be taken together. However, it is important to talk to your doctor or pharmacist before taking any medications together.

What Are the Benefits of Taking Benadryl and Nyquil Together?

Taking Benadryl and Nyquil together may provide relief from symptoms of both colds and allergies, such as congestion, sneezing, and runny nose.

Are There Any Risks of Taking Benadryl and Nyquil Together?

Taking Benadryl and Nyquil together can increase the risk of side effects. It is important to talk to your doctor or pharmacist before taking any medications together.

How Do I Take Benadryl and Nyquil Together?

Taking Benadryl and Nyquil together can be done safely if done correctly. Follow the instructions on the package labels and talk to your doctor or pharmacist for further guidance.

Is it safe to take Benadryl and Nyquil together every day?

Generally, it is not recommended to take Benadryl and Nyquil together every day. Taking both medications together every day can increase the risk of side effects and other potential risks.

It is important to speak with a healthcare provider prior to taking both medications together on a daily basis.

Last Words

Benadryl is an antihistamine used for treating allergies and Nyquil is a popular over-the-counter cold medicine. 

Taking both medications together could cause severe side effects so it’s important to understand if this combination is safe. 

We’ll take a look at how each medication works and explore the risks involved in taking them together. While providing tips on other ways to help relieve symptoms of cold and flu season safely and effectively. 

Thanks again for your question and please feel free to reach back out again!

Related: How Long To Separate Tylenol From NyQuil


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